Some among various techniques for modularizing a NC (numerical controller) are OSACA (Open System Architecture for Controls within Automation systems) in Europe, OMAC (Open Module Architecture Controls) in U.S., OSEC (Open System Environment for Controllers) in Japan, etc. Prior arts concerned with these techniques are introduced in a paper directed to a holonic NC based on a holonic manufacturing paradigm (Kurth 1994, Suh et al. 1998); to a TRUE-CNC serving as a NC system having a CAD, a CAPP, a CAM, a CNC (Computer-based Numerical Control), a monitoring and a verifying function (Yamajaki et at. 1997); and to a production cell based on a programming interface (Brouer et al. 1997), etc. These conventional techniques are developed to overcome a closed structure of prior NCs. However, they do not specify therein a module and its structure for realizing an intelligent NC controller.